A comprehensive review of technologies used to improve the performance of PV systems in a view of cooling mediums, reflectors design, spectrum splitting, and economic analysis.

Solar photovoltaic panels are increasingly being used throughout the world, particularly in Egypt, where a station has been constructed in the city of Aswan with a capacity of 1480 MW, and is classified as one of the largest photovoltaic plants in the Middle East country, where photovoltaic systems are characterized as environmentally friendly and do not produce any pollutants, and photovoltaic systems have the ability to operate with diffuse radiation. It is therefore very important to understand how photovoltaic panels respond to changing weather conditions and how climate conditions affect the performance of photovoltaic cells, as only 15-20% of solar radiation can be converted to electricity, while the rest is wasted as thermal heat. There are two very important factors influencing the efficiency of the photovoltaic cells: the cell temperature and the solar radiation intensity on the photovoltaic cells. Cooling of the optical surfaces is one of the main factors that must be considered in order to achieve the highest efficiency when operating the solar PV systems. By using the appropriate cooling technology for the photovoltaic cells, the electrical efficiency is improved, and the cell degradation rate is decreased over time, which increases the life span of the PV panels. In some applications, such as industrial and domestic applications, excess energy removed with cooling technology could be used. The cooling mediums used to cool the PV panels are water, air, PCM, and nanofluid. Also, the spectral splitting utilization represents a good solution for hybrid solar photovoltaic-thermal applications to obtain higher performance of the photovoltaic. This paper gives a brief analysis of technologies used to improve PV systems efficiency in terms of the nature of cooling media, spectral splitting, and reflectors. Moreover, the economic study of these techniques is presented to demonstrate their economic feasibility. The aims of the present review paper are to provide good knowledge and understanding of all technologies used to improve the performance of PV systems and demonstrate the economic feasibility of these technologies.